Intervertebral instrument, implant, and method

ABSTRACT

An intervertebral instrument includes a shaft having distal and proximal ends. The proximal end of the shaft includes an attaching feature connected to handle. The shaft defines a pair tracks disposed along a portion of the surface thereof. The distal end includes a pair of wings. Each track guides instruments and implants along the intervertebral instrument. The implants are configured to receive bone graft or bone enhancers. The distal end of the shaft may include a removably attachable tip configured to engage the implants. The implants and the removably attachable tip form an implantable intervertebral disk. An intervertebral instrument and implant kit is also disclosed. A method of inserting intervertebral implants is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of, and priority, to U.S.Provisional Patent Application Ser. No. 61/068,564, filed Mar. 7, 2008,the entire contents of which are incorporated by reference herein.

BACKGROUND

1. Technical Field

This application relates to intervertebral distracting instruments,intervertebral disc implants, and a method for inserting intervertebraldisc implants between affected vertebrae to achieve spinal fusion.

2. Background of Related Art

The human spine is composed of thirty-three vertebrae at birth andtwenty-four as a mature adult. Between each pair of vertebrae is anintervertebral disc, which maintains the space between adjacentvertebrae and acts as a cushion under compressive, bending, androtational loads and motions. A healthy intervertebral disc has a greatdeal of water in the nucleus pulposus, which is the center portion ofthe disc. The water content gives the nucleus a spongy quality andallows it to absorb spinal stress. Excessive pressure or injuries to thenucleus can cause injury to the annulus, which is the outer ring thatholds the disc together. Generally, the annulus is the first portion ofthe disc that experiences injury. These injuries are typically in theform of small tears. These tears heal by scar tissue. The scar tissue isnot as strong as normal annulus tissue. Over time, as more scar tissueforms, the annulus becomes weaker. Eventually this can lead to damage ofthe nucleus pulposus. The nucleus begins to lose its water content dueto the damage, i.e., it begins to dry up. Because of water loss, discslose some of their ability to act as a cushion. This can lead to evenmore stress on the annulus and still more tears as the cycle repeats. Asthe nucleus loses its water content it collapses, allowing the vertebraeabove and below the disc space to move closer to one another. Thisresults in a narrowing of the disc space between the two vertebrae. Asthis shift occurs, the facet joints located at the back of the spine areforced to shift. This shift changes the way the facet joints worktogether, and thus, can cause problems in the facet joints as well.

When a disc or vertebra is damaged due to disease or injury, standardpractice is to remove all or part of the intervertebral disc, insert anatural or artificial disc spacer, and construct an artificial structureto hold the affected vertebrae in place to achieve a spinal fusion. Theprocedure may be accomplished using various approaches such asanteriorly, posteriorly and transforaminally. Depending on whichapproach is used, a specific geometry spacer device is selected.

Anteriorly approached procedures are preferred when one of theclinician's goals is to use a spacer device that most closely matchesthe footprint of the vertebral body. This maximum sized footprint alsoallows for the introduction of a significant amount of bone graft. Itmay also promote a better bone fusion. The preferred instrument tointroduce an anterior spacer device is a “sled” style instrument. Thesled provides the necessary vertebral body distraction and a path forintroducing the device. Unfortunately, the sleds currently available arevery bulky, complicated to use, and obstruct the clinician's workingview.

For the above stated reasons, a need exists for a system that includesan instrument for distracting the vertebral bodies in such a way thatdoes not obstruct the surgeon's view and still allows additional discspace work to be performed. The system must also provide a pathway forintroducing the device into the intervertebral disc's space.

SUMMARY

The present disclosure relates to an intervertebral instrument includinga shaft having distal and proximal ends. The proximal end of the shaftincludes an attaching feature for enabling the shaft to attach to ahandle for manipulating the shaft. The shaft defines at least one trackat least partially disposed along a portion of the surface thereof. Thedistal end of the shaft includes a pair of wings for distracting anintervertebral disk space defined between two vertebrae. Each track isconfigured and dimensioned to guide instruments and intervertebralimplants used in intervertebral procedures toward the intervertebraldisk space. The intervertebral instrument is configured and dimensionedto be utilized with a plurality of different sized patients.

In another embodiment of the intervertebral instrument, the distal endof the shaft includes a removably attachable tip configured anddimensioned to engage the implants. The removably attachable tip isconfigured and dimensioned to keep implants affixed thereto. Theintervertebral implants and the removably attachable tip are configuredand dimensioned to collectively function as an implantableintervertebral disk. The implantable intervertebral disk is configuredand dimensioned to receive bone graft or bone enhancers to enable boneingrowth.

The intervertebral implants include a pair of members. The members eachhave a body with top, bottom, inside, and outside surfaces. The top andbottom surfaces include ridges disposed thereon. The inside surface hasat least one protuberance configured and dimensioned to engage theintervertebral instrument. At least one of the members includes at leastone passage for receiving bone graft or bone enhancers to enable boneingrowth. As such, at least one of the members is configured anddimensioned to receive bone graft or bone enhancers to enable boneingrowth.

In one embodiment, the intervertebral implant includes a removablyattachable portion configured and dimensioned to connect each member.The removably attachable portion includes a pair of tracks. Each trackis configured and dimensioned to engage the at least one protuberance ofeach member. Each member is configured and dimensioned to remain affixedto the removably attachable portion. The combination of each member andthe removably attachable portion collectively function as an implantableintervertebral disk when the removably attachable portion and eachmember are collectively detached from the intervertebral instrument.

An intervertebral instrument and intervertebral implant kit is alsoenvisioned and includes an intervertebral instrument and at least oneintervertebral implant in accordance with the present disclosure. Thekit can also include a handle disposed at the proximal end of the shaftfor manipulation of the shaft. In another embodiment of the kit, theshaft includes a removably attachable tip disposed at the distal endthereof. In this embodiment of the intervertebral instrument andintervertebral implant kit, the removably attachable tip and the atleast one intervertebral implant are configured and dimensioned tocollectively function as an implantable intervertebral disk.

One aspect of the present disclosure contemplates a method for insertingan intervertebral implant including the steps of inserting anintervertebral instrument into the intervertebral disk space, advancingan intervertebral implant along a track toward the intervertebral diskspace, inserting the implant and a removably attachable tip in theintervertebral disk space, and selectively applying bone graft or boneenhancers into the intervertebral disk space for bone ingrowth. The stepof inserting the intervertebral instrument can be performed using ananterior, a posterior, a lateral, or a transforaminal approach. Duringthe process, a user can selectively pass complementary instruments downthe at least one track for facilitating the insertion of the at leastone implant and any removably attachable tip attached thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the presentdisclosure will become more apparent in light of the following detaileddescription when taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a perspective view of one of two identical members of anintervertebral implant in accordance with the present disclosure;

FIG. 2 is a perspective view, with parts separated, of one embodiment ofthe intervertebral instrument including a handle connected to theproximal end in accordance with the present disclosure;

FIG. 3 is a perspective view of the intervertebral instrument of FIG. 2(without the handle) including one embodiment of a complementaryinstrument attached thereto;

FIG. 4 is a perspective view of the intervertebral instrument of FIG. 2(without the handle) including another embodiment of a complementaryinstrument attached thereto;

FIG. 5 is a perspective view of the intervertebral instrument of FIGS.2-4 having the one member of FIG. 1 of the two identical members of theintervertebral implant attached on one side of the distal end thereofand the second member of the two identical members of the intervertebralimplant attached on the other side of the distal end thereof, theintervertebral instrument including a handle connected to the proximalend thereof;

FIG. 6 is a perspective view, with parts separated, of anotherembodiment of the intervertebral instrument in accordance with thepresent disclosure;

FIG. 7 is a perspective view of the intervertebral instrument of FIG. 6having the one member of FIG. 1 of the two identical members of theintervertebral implant attached on one side of the distal end thereofand the second member of the two identical members of the intervertebralimplant attached on the other side of the distal end thereof; and

FIG. 8 is a perspective view of a fusion implant disposed between twoadjacent vertebrae in accordance with the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Various embodiments of the present disclosure will now be described indetail with reference to the drawings, wherein like reference numeralsidentify similar or identical elements. In the drawings and in thedescription that follows, the term “proximal,” will refer to the end isclosest to the operator, while the term “distal” will refer to the endthat is farthest from the operator. In addition, the term “cephalad” isused in this application to indicate a direction toward a patient'shead, whereas the term “caudad” indicates a direction toward thepatient's feet. Further still, for the purposes of this application, theterm “medial” indicates a direction toward the middle of the body of thepatient, whilst the term “lateral” indicates a direction toward a sideof the body of the patient (i.e., away from the middle of the body ofthe patient). The term “posterior” indicates a direction toward thepatient's back, and the term “anterior” indicates a direction toward thepatient's front. In the following description, well-known functions orconstructions are not described in detail to avoid obscuring the presentdisclosure in unnecessary detail.

Referring now to the drawings, in which like reference numerals identifyidentical or substantially similar parts throughout the several views,FIG. 1 illustrates one portion of two identical portions of anintervertebral implant 10 (both portions shown in FIG. 5). In accordancewith the present disclosure, the intervertebral implant 10 includesfirst and second members 20, 30. Each member 20, 30 has a body 22, 32with a top surface 22 a, 32 a, a bottom surface 22 b, 32 b, an insidesurface 22 c, 32 c, and an outside surface 22 d, 32 d. The top surface22 a, 32 a and the bottom surface 22 b, 32 b include ridges 24, 34disposed thereon. The inside surface 22 c, 32 c has a first protuberance26, 36 distally disposed thereon and a second protuberance 28, 38proximally disposed thereon. Each protuberance 26, 28, 36, 38 isconfigured and dimensioned to engage an intervertebral instrument 100,200 (FIGS. 2 and 6). Each member 20, 30 has a channel 25, 35 cuttherethrough. Each channel 25, 35 extends from a respective firstopening 25 a, 35 a disposed on each respective inside surface 22 c, 32c, to a respective second opening 25 b, 35 b disposed on each respectiveoutside surface 22 d, 32 d. In addition, a longitudinal passage 21, 31extends through each respective member 20, 30 from a respective firstaperture 21 a, 31 a disposed on the respective top surface 22 a, 32 a toa respective second aperture 21 b, 31 b disposed on the respectivebottom surface 22 b, 32 b. Each channel 25, 35 and each longitudinalpassage 21, 31 are configured and dimensioned to receive bone graft orbone enhancers to enable bone ingrowth.

Referring to FIGS. 2-5, an intervertebral instrument 100 includes ashaft 110 having distal and proximal ends and an attaching feature 150.The shaft 110 includes a sleeve 112 defining a first track 114 (FIG. 2)and a second track 116 (FIG. 5) extending longitudinally along a portionof opposing external surfaces of the shaft 110. Each track 114, 116 isconfigured and dimensioned to guide instruments used in intervertebralprocedures, such as the first instrument 80 shown in FIG. 3 or thesecond instrument 90 shown in FIG. 4 (each of which is described below),as well as the respective members 20, 30 of implants 10 toward theintervertebral disk space. The distal end of the sleeve 112 includes apair of wings 118, 120 orthogonally disposed relative to first andsecond track 114, 116. The wings 118, 120 interconnect with each otherby a contoured distal groove 119. The pair of wings 118, 120 areconfigured and dimensioned to distract an intervertebral disk spacedefined between two vertebrae.

Referring additionally to FIGS. 2 and 5, a handle 160 is removablyattachable to the attaching feature 150 at the proximal end of the shaft110. The handle 160 includes a connector 162 centrally attached to anactuator 164 at the proximal end of the connector 162. The actuator 164includes grips 166 for engagement by a user's hand. The connector 164 isconfigured and dimensioned to distally and removably connect to theattaching feature 150 about the proximal end of the attaching feature150. As such, the handle 160 is configured and dimensioned to enable theshaft 110 to be manipulated.

Referring now to FIG. 3 the first instrument 80 includes a shaft 82 anda distracting tip 84. The shaft 82 is configured and dimensioned toengage the sleeve 112, 212 of each of the intervertebral instruments100, 200 (FIGS. 2 and 6) so that the distracting tip 84 can bepositioned within the intervertebral disk space in order to furtherfacilitate the distraction of adjacent vertebrae “V1” and “V2” (FIG. 8).The distracting tip further includes pointed heads 86 disposed at thedistal end thereof, at least one cavity 88 disposed in the body thereoffor receiving members 20, 30, and a measuring guide 89 disposed on theexternal surface of the body thereof for measuring the placement ofmembers 20, 30.

Referring now to FIG. 4 the second instrument 90 includes a shaft 92 anda distracting tip 94. The shaft 92 is configured and dimensioned toengage the sleeve 112, 212 of each of the intervertebral instruments100, 200 (FIGS. 2 and 6) so that the distracting tip 94 can bepositioned within the intervertebral disk space in order to furtherfacilitate the distraction of adjacent vertebrae “V1” and “V2” (FIG. 8).The distracting tip further includes a top platform 96 and a bottomplatform 98, each platform 96, 98 including ridges 97 for engagingvertebrae “V1” and “V2.” Each platform 96, 98 is separated by a space 99for receiving members 20, 30.

In a second embodiment of the intervertebral instrument, as illustratedin FIGS. 6 and 7, the intervertebral instrument 200 is substantiallysimilar to the intervertebral instrument 100. However, theintervertebral instrument 200 includes a shaft 210 with tracks 214, 216and a removably attachable tip 270 at the distal end thereof. Theremovably attachable tip 270 removably attaches to the distal end of thesleeve 212 of the intervertebral instrument 200 by a pair of stems 213a, 213 b. The removably attachable tip 270 is configured and dimensionedto engage the members 20, 30 of the implant 10. A pair of tracks 272,274 is partially longitudinally defined along opposing external surfacesof the removably attachable tip 270. The tracks 272, 274 are configuredand dimensioned to guide the implants 10 (FIG. 7) and their respectivemembers 20, 30 thereon. The removably attachable tip 270 is configuredand dimensioned to keep the implants 10 affixed thereto. The removablyattachable tip 270 is configured and dimensioned to engage eachprotuberance 26, 28, 36, 38 of each respective member 20, 30 (FIG. 1).As illustrated in FIG. 8, the intervertebral implant 10 and theremovably attachable tip 270 are configured and dimensioned tocollectively function as a unitary fusion implant 300 when the removablyattachable tip 270 and each member 20, 30 are collectively detached fromthe intervertebral instrument 200. The fusion implant 300 is configuredand dimensioned to remain implanted in the intervertebral disc space,i.e., between adjacent vertebrae V.

It is contemplated and within the scope of the present disclosure thatthe intervertebral instruments 100, 200, implants 10, and implantableintervertebral disks 300 may be used during procedures performedanteriorly, posteriorly, laterally, and transforaminally. For example,using an anterior approach, minimal disc space preparation is performedand the intervertebral instrument 100, 200 is inserted into the discspace, preferably on its midline. The intervertebral instrument 100, 200is rotated approximately 90 degrees engaging the endplates andseparating them by the height of the instrument. Several sizedintervertebral instruments 100, 200 are contemplated to allow for thevariations between patients. Additional, complimentary instruments 80,90 may be passed down the tracks 114, 116, 214, 216 to prepare the discspace for the implant 10, or the implantable intervertebral disk 300.Additional complimentary instruments include, but are not limited to,box chisels, scrapers and trial implants. When the final intervertebralimplants have been appropriately sized, the final intervertebralimplants may be packed with bone graft and passed down the tracks 114,116, 214, 216 of the corresponding intervertebral instrument 100, 200.After final placement of the intervertebral implant 10, or theimplantable intervertebral disk 300 has been achieved, theintervertebral instrument 100, 200 may be removed and the subsequentvoid may be filled with additional bone graft, potentially more thanwith a typical anterior approach implant.

Specifically with respect to intervertebral instrument 200, theremovably attachable tip 270 is made of an implant grade material,preferably PEEK. In doing so, the members 20, 30 are passed down theintervertebral instrument 200 so that they may engage and lock to theremovably attachable tip 270. As such, when the intervertebralinstrument 200 is removed, the implantable intervertebral disk 300becomes a one-piece design and the removably attachable tip 270 and themembers 20, 30 collectively remain in the disc space as a unitaryimplant 300. This design provides increased strength.

Each of these intervertebral instruments 100, 200 are configured anddimensioned to be used with a plurality of different sized patients.

While several embodiments of the disclosure have been shown in thedrawings, it is not intended that the disclosure be limited thereto, asit is intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of preferred embodiments. Thus the scope of theembodiments should be determined by the appended claims and their legalequivalents, rather than by the examples given.

For example, it is within the scope of the present disclosure thatmembers 20, 30 may be uniform unit without the removably attachable tip270, i.e. a single piece intervertebral implant.

1. An intervertebral instrument including a shaft having distal andproximal ends, the shaft defining at least one track at least partiallydisposed along a portion of the surface of the shaft, wherein the distalend is configured and dimensioned to distract an intervertebral diskspace defined between two vertebrae, and wherein the at least one trackis configured and dimensioned to guide instruments and implants used inintervertebral procedures toward the intervertebral disk space.
 2. Theintervertebral instrument according to claim 1, wherein the distal endof the shaft includes a removably attachable tip.
 3. The intervertebralinstrument according to claim 2, wherein the removably attachable tip isconfigured and dimensioned to engage the implants.
 4. The intervertebralinstrument according to claim 3, wherein the removably attachable tip isconfigured and dimensioned to keep the implants affixed thereto, whereinthe implants and the removably attachable tip are configured anddimensioned as a unitary implant.
 5. The intervertebral instrumentaccording to claim 4, wherein the implantable intervertebral disk isconfigured and dimensioned to receive bone graft or bone enhancers tofacilitate bone ingrowth.
 6. The intervertebral instrument according toclaim 1, wherein the intervertebral instrument is configured anddimensioned to be used with a plurality of different sized patients. 7.The intervertebral instrument according to claim 1, wherein the proximalend of the shaft includes an attaching feature for enabling the shaft toattach to a handle for manipulating the shaft.
 8. The intervertebralinstrument according to claim 1, wherein the distal end of the shaftincludes a pair of wings for distracting the intervertebral disk space.9. An intervertebral implant, comprising: a pair of members, each memberhaving a body with top, bottom, inside, and outside surfaces, the topand bottom surfaces including ridges disposed thereon, the insidesurface having at least one protuberance, the at least one protuberanceconfigured and dimensioned to engage an intervertebral instrument,wherein at least one of the members is configured and dimensioned toreceive bone graft or bone enhancers to enable bone ingrowth.
 10. Theintervertebral implant according to claim 9, wherein at least one of themembers includes at least one passage for receiving bone graft or boneenhancers to enable bone ingrowth.
 11. The intervertebral implantaccording to claim 9, wherein each member is removably affixed to oneanother.
 12. The intervertebral implant according to claim 11, whereinthe intervertebral instrument further comprises a removably attachableportion that affixes each member to one another wherein the removablyattachable portion includes a pair of tracks and wherein each track isconfigured and dimensioned to engage the at least one protuberance ofeach member.
 13. The intervertebral implant according to claim 12,wherein each member is configured and dimensioned to remain affixed tothe removably attachable portion, wherein the combination of each memberand the removably attachable portion define an implantableintervertebral disk when the removably attachable portion and eachmember are separated from the intervertebral instrument.
 14. Anintervertebral instrument and implant kit comprising: an intervertebralinstrument including a shaft having distal and proximal ends, the shaftdefining at least one track at least partially disposed along a portionof the surface thereof, wherein the distal end is configured anddimensioned to distract an intervertebral disk space defined between twovertebrae, and wherein the at least one track is configured anddimensioned to guide instruments and intervertebral implants used inintervertebral procedures toward the intervertebral disk space; and atleast one intervertebral implant including a pair of members, eachmember having a body with top, bottom, inside, and outside surfaces, thetop and bottom surfaces including ridges disposed thereon, the insidesurface having at least one protuberance, the at least one protuberanceconfigured and dimensioned to engage the intervertebral instrument,wherein at least one of the members is configured and dimensioned toreceive bone graft or bone enhancers to enable bone ingrowth.
 15. Theintervertebral instrument and implant kit according to claim 14, furthercomprising a handle disposed at the proximal end of the shaft formanipulation of the shaft.
 16. The intervertebral instrument and implantkit according to claim 14, wherein the shaft further includes aremovably attachable tip disposed at the distal end thereof.
 17. Thenintervertebral instrument and implant kit according to claim 16, whereinthe removably attachable tip and the at least one intervertebral implantdefine an implantable intervertebral disk.
 18. A method for inserting anintervertebral implant comprising: providing an intervertebralinstrument including a shaft having distal and proximal ends, the shaftdefining at least one track at least partially disposed along a portionof the surface thereof, wherein the distal end is configured anddimensioned to distract an intervertebral disk space defined between twovertebrae, and wherein the at least one track is configured anddimensioned to guide instruments and implants used in intervertebralprocedures toward the intervertebral disk space; inserting theintervertebral instrument into the intervertebral disk space; advancingat least one implant down the at least one track toward theintervertebral disk space; inserting the at least one implant and anyremovably attachable tip attached thereto in the intervertebral diskspace; and selectively applying bone graft or bone enhancers into theintervertebral disk space for bone ingrowth.
 19. The method of claim 18,wherein the step of inserting the intervertebral instrument is performedusing at least one of the following approaches: anterior, posterior,lateral, or transforaminal.
 20. The method of claim 18, furthercomprising the step of: selectively passing complementary instrumentsdown the at least one track for facilitating the insertion of the atleast one implant and any removably attachable tip attached thereto.